Engine Swap Info

There are a number
of considerations that will be discussed in regards to swapping
in a larger engine. (Please note that most of this info was compiled
in 1996, so some of it may be dated.) The most popular engine choices tend to be
Buick V6s, Chevy V6s and small block Chevy V8s. Ford V8s are
also fairly popular. Occasionally one will see a big block V8
lurking under Toyota sheetmetal, but this swap is fairly rare
and requires serious rework of the truck.

Clicking on any category will take you right
to that particular section.

ENGINE CHOICES

There are a number of V6 and V8 engines that can be swapped
into a Toyota. Some of these are discussed below.

BUICK V6
The 3.8 liter Buick engine is often used in Toyota conversions.
This engine has been used extensively in performance and race
applications, and as such, there are many hop-up parts and
accessories available for the it. The Buick V6 is a bit smaller
and lighter than the Chevy or Ford V6s, but is somewhat heavier
than the 3.0 liter Toyota V6. Some Buick V6s (odd ifre I believe)
have a moderate vibration problem and may tend to run a bit on the
hot side.

There is also a turbocharged version of the Buick engine that
provides quite a punch for a light truck. However, be cautioned
that such a swap requires careful thought to obtain adequate
engine cooling especially in cases where the truck will be
driven slowly or for some reason have limited airflow.
Modification of the exhaust, truck frame, and body will
most likely be needed to get this engine to fit.

CHEVY V6
An engine that has gained considerable swap popularity recently
is the 4.3 liter GM Vortex engine. This engine came from the
factory in several configurations including: carbureted,
throttle-body injected (165 HP), and central-point injected
(~200 HP). This is a torquey engine, and uses the same block
design as the small block Chevy less two cylinders. Pistons,
rods, bearings, etc. are all interchangeable. It also uses
roller lifters.

The only flaw in this engine is a slight imbalance condition
at about 1200 rpm. About 1993 Chevy revised this engine
by adding a crank driven counter-balance to eliminate
this slight vibration. Also, engines from the mid '80s and newer
use a single serpentine belt with an automatic tensioner.

CHEVY V8
There is a wide variety of Chevy V8 small blocks available
ranging from older Corvette or carbureted muscle car engines
to the modern throttle body or tuned port engines. Late model
engines can be found in both 5.0 liter and 5.7 liter sizes.
Parts selection for these engines is enormous and there are
lots of salvage yard engines around.

The small block Chevy V8 is about 4-5 inches longer than the
Chevy V6 and weighs quite a bit more. The V8 can be used in a
conversion but will require firewall modifications due to the
added length and the rear mounted distributor. Installing the
V8 also requires that the front grill sheetmetal area be
modified and the radiator be relocated forward about an inch
and a half. A stiffer front suspension is also required with
a V8 conversion and a body lift may be required for distributor
clearance, depending on size and style used.

FORD V6
The Ford V6 swap has not really gained much popularity.

FORD V8
Ford small block V8s are shorter and narrower than the small
block Chevy engines. Also, the distributor is mounted on the
front of the engine, making fitting of a Ford V8 into a vehicle
easier than fitting a Chevy V8.

There are a number of Ford V8 engines available, both in
carbureted and fuel injected form. By far, those of most
interest are the 5.0 liter (302 cubic inch) multi-point fuel
injected engines from either the full-size truck line or the
performance engines from the Mustang line. There are several
companies that are now familiar with setting up the fuel
injection systems on these engines to work in other vehicles.

ENGINE CHOICE
Any of the above engines will fit well between the Toyota frame
rails and should allow use of a regular air cleaner under the
stock hood. The one exception is the Turbo conversion which
will require a 2-3 inch body lift in order to clear the air
intake and exhaust components. Conversions generally require
a 3 inch or more suspension lift in order to have oil pan
clearance and/or retain adequate front suspension travel.

In general, an engine can be legally swapped into a vehicle
if the engine is the same year as the truck, or newer, and
all stock engine emissions gear is retained. However, swap
laws do vary from state to state. Before doing any swap,
check your local laws to see exactly what is legal.

TRANSMISSIONS

Transmission choices for an engine swap fall into four main
categories: stock Toyota or non-Toyota manual, and stock
Toyota or non-Toyota automatic transmissions. Performance,
installation and reliability of each of these will be
discussed briefly.

TOYOTA MANUAL TRANSMISSIONS

In order to use a Toyota manual transmission in a V6 or V8
engine swap, it must be of the type with a removable
bellhousing. 1979 to early 1981 4 speeds and late 1983 and
newer 5 speeds came with removable bell housings. There are
kits available to mate any of these transmissions to a V6 or
V8. However, the 4 speed transmissions and the pre 1985 5
speeds are generally too weak or problem prone to be considered
for such engine swaps.

Consequently, the 1985 and newer 5 speed transmissions are
the best choice if a Toyota manual transmission is to be used.
Two different models have been used since 1985, one type for
the 4 cylinder trucks and another for the turbo and V6 trucks.
The latter unit being somewhat beefier in critical areas. Both
of these models are supposedly quite strong and able to
withstand sane amounts of V6 and V8 power provided a sturdy
aftermarket clutch is used. However, rebuild cost for a blown
5 speed transmission is high and if you feel that you won't
be able to keep your foot out of the gas, or you must run
large tires, it's probably wise to consider a transmission
swap as well.

Kits are available to mate Toyota manual transmissions to the
Buick V6, Chevy 4.3l V6, Chevy V8s from 265 to 400 cubic inches,
and Ford V8s from 260 to 351 cubic inches. These kits typically
include a conversion bellhousing, clutch fork, throw-out bearing,
custom clutch disk and slave cylinder to fit the new bellhousing.
The stock clutch master cylinder can be retained.

NEW VENTURE MODEL 4500
The NV4500 has been used in GM and Dodge trucks since 1992. It
is a five speed manual transmission that is fully synchronized
in all forward gears, and also synchronized in reverse in the
Dodge versions. First gear ratios have been available in 4.01:1,
5.61:1, and 6.34:1. Fifth gear ratio is 0.73:1 offering a 27%
overdrive.

The transmission is very rugged having been offered in 3/4 ton
full-size trucks. The main case of the transmission is built
from cast iron, with some of the less critical parts made from
aluminum.

Adapters are available to mate the NV4500 transmission to the
Toyota transfer case. (Watch this carefully though as not all
models of the NV4500 can be used with this swap.) While cost
for this transmission is
usually high, it is probably the one of the best manual
transmissions ever made for use in a 4WD truck. The very low
first gear and fifth gear overdrive combine to provide a
transmission that does equally well whether crawling over rocks
or screaming down the highway. And this transmission is one
way to retain a manual transmission in your truck and still
pump lots of V8 power through it.

GM MUNCIE 4 SPEED
The Muncie 4 speed was used in GM cars for years. Because of
its strength, it is often found behind healthy V8 engines. It
has also been a popular transmission because of the availability
of numerous different gear ratio sets. It is possible to purchase
the components to mate a Muncie to a Toyota transfer case.
However, this swap does require a body lift, custom mounting
and sheetmetal work, shifter linkage, clutch setup, and driveshaft
modifications.

FORD T-18 FOUR SPEED
The Ford T-18 is essentially the same transmission that is so
sought after by Jeep owners. It can be bolted to a bellhousing
to mate to a Ford, Chevy, or AMC engine, and adapter kits are
available to mate its output to a Toyota transfer case. It is a
4 speed manual transmission with a low 1st gear. This granny gear
is often greater than 6:1 offering outstanding crawling capability.
This transmission is also very rugged and dependable. When used
behind a V6 or V8 engine, this transmission will require use of
a body lift due to the large transmission case size.

BORG WARNER T-5 WORLD CLASS
Late model Camaros and Mustangs have used this 5 speed transmission
combined with small block V8 power with excellent results. This
transmission, while not offering a very low 1st gear (only about 4:1),
offers a close ratio gear set with a short, quick shifter throw.
This transmission will work well for truck applications where a
granny gear is not needed. Adapter kits are available to mate this
transmission to the Toyota transfer case.

DAHAITSU MANUAL TRANSMISSIONS
Mark's 4WD in Australia sells two types of heavy duty truck transmissions
with adapter for use on the Toyota 4WD truck. The first is a Daihatsu
truck 5 speed found in the Daihatsu Delta truck line. It offers a 5.69:1
first gear combined with a 21% overdrive gear. The second transmission
is a heavy duty Toyota truck model with a 5.15:1 first gear and 17%
overdrive. Both transmissions are said to adequately withstand the high
loads of V8 engines and complete installation kits are available for each.
As a side note, Mark's 4WD also supplies swap kits for many of the popular
engines available in Australia including Mitsubishi, Holden, Commodore,
and Toyota (diesel) engines. They can also perform 4 speed to 5 speed
conversion on some older Toyota transmissions.

AUTOMATIC TRANSMISSIONS

TOYOTA AUTOMATIC TRANSMISSIONS
Adapter kits have been available to mate the Aisin Warner AW4 4
speed automatic to a Chevy V6 or V8. The AW4 is an electronic
shifting transmission and has been used in Toyotas, Jeep Cherokees,
and Isuzu Troopers. The conversion kit consists of a replacement
bellhousing to mate the AW4 to the Chevy engine and a new flywheel
that accepts a torque converter from a six cylinder Jeep.

There are two drawbacks to this conversion. First, the Jeep torque
converter is quite expensive, and there have been reports of
numerous problems in getting the electronic shifting transmission
to function properly. (This kit may no longer be available.)

GM TH350 AUTOMATIC
The three speed GM Turbo Hydromatic 350 is probably the most popular
automatic transmission ever put behind a V8. It has been used in a
wide variety of cars and trucks, and is readily available. These
transmissions can be purchased cheaply, and there are lots of
modification parts available for them. Gear ratios are: first,
2.52:1; second, 1.52:1; third 1.00:1. When doing an engine
conversion, this is the easiest swap transmission to install.
Note, when using a TH350 transmission on a Buick V6 it is
necessary that the transmission come from a Buick, Oldsmobile,
or Pontiac to provide the correct bellhousing bolt pattern.

Late model versions of the TH350 provide computer controlled
torque converter lockup in 3rd gear. This action drains the
torque converter of fluid and eliminates all slip to make the
transmission more efficient and reduce heat. These models can
be modified to provide a mechanically actuated lockup for use
on non-computer engines, or in cases where the computer is not
used to control the transmission.

GM TH400 AUTOMATIC
It is possible to install a TH400 three speed automatic in a
Toyota truck and get the adapters needed to mate it to the stock
transfer case. However, the ruggedness of the TH400 is rarely
necessary in such applications. The TH400 wastes quite a bit more
energy than the TH350, yet the TH350 can be made nearly as strong
as a stock TH400 by replacing the sprag, and other components, and
upgrading them to stronger units. Standard gear ratios are: first,
2.48:1; second, 1.48:1; third 1.00:1. One advantage to the TH400
is that there are several sets of gear ratios available for them,
including a low 3.00:1 first gear.

GM 700R4 4 SPEED AUTOMATIC
The 700R4 uses a 3.06:1 first gear and has a 30% (0.70:1 4th
gear ratio) overdrive. Second gear is 1.62:1 and third is 1.00:1.

In factory applications, the 700R4 uses computer control to
electronically lockup the torque converter in 3rd and 4th gears.
As in the late model TH350, it is possible to have the transmission
built with an aftermarket mechanical lockup system. This allows
lockup to engage shortly after the transmission shifts into 3rd
gear and remains locked up in 4th. A TV cable runs from the
carburetor or injector body to the transmission. This cable
helps control upshifts and downshifts in the transmission.

Only post 1985 transmissions, or those retrofitted or rebuilt with
post 1985 parts should be used. Earlier units were problematic and
the high gear lockup was inconsistent and unreliable.

FORD C-4/C-5/C-6 AUTOMATICS
The Ford C-4 3 speed automatic was used for many years in Ford
F-Series trucks behind small block V8s. It is a small transmission
making it very desirable as far as fitting one in a tight swap
situation. Gear ratios are: first, 2.46:1; second, 1.46:1; third
1.00:1.

The C-5 transmission uses a torque converter lockup similar to
those found in some of the GM automatics. This transmission has
been in use since the early 1980s and has been used in both
Rangers and F-Series trucks. Gear ratios are the same as those
used in the C-4.

The Ford C-6 3 speed automatic has been used behind both small
and big block V8s. It is the high-power version of the 3 speed
autos. Gear ratios are the same as those used in the C-4.

FORD AOD/E40D 4 SPEED AUTOMATICS
Ford 4 speed automatic overdrive transmissions have also been
used in Rangers, F-Series trucks, and numerous cars. The AOD
is the older of the two having been introduced in about 1980.
The E40D begun arriving in vehicles in the late 1980s and was
used behind small and big block V8s, and V6s as well. The E40D
torque converter is electronically controlled and requires use
of the Ford computer for shift control. Gear ratios for the Ford
4 speeds are: first, 2.40:1; second, 1.47:1; third 1.00:1; fourth,
0.67:1.

TRANSMISSION CHOICE
There are pros and cons to choosing either a manual or automatic
transmission. A manual is generally considered to be more reliable
and definitely provides better compression braking than an automatic.
However, an automatic provides smoothness and ease of use, and is
kinder to other drivetrain parts due to the fluid coupling as
opposed to a mechanical coupling in a manual transmission. There
are also installation considerations for each type when performing
an engine swap.

When swapping in a non-stock manual transmission, it will be necessary
to ensure that the shift mechanism fits under the floorboard and is
adjusted properly, and that the shift lever is located practically in
the cab. You will also need to provide an appropriate slave cylinder
to operate the clutch. If the Toyota master cylinder is inadequate,
it will have to be modified or replaced as well.

Installing an automatic transmission requires different modifications.
In almost all cases, a cable operated shifter will be the easiest to
install. A large number of aftermarket units are available. It will be
necessary to provide transmission oil cooling in the radiator and also
possibly in a remote oil cooler. Oil lines will have to be run to accommodate
the cooler(s). A transmission kickdown or TV cable will be needed and you
may have to fabricate brackets for these. It is also a good idea to
incorporate the neutral safety and reverse light switches from the shifter
into the wiring harness of the truck. The neutral safety switch will prevent
the starter from engaging in any position except Park or Neutral.
A dip stick, tube, and inspection cover will also be needed.

MOTOR MOUNTS

There are two options for motor mounts when doing an engine conversion.
You can buy bolt-in mounts that bolt to the stock mounts, or you can
fabricate new ones from scratch. Buying bolt-in mounts is easier and
quicker. Building your own is less expensive and allows you to position
the engine exactly as you want it.

Homebuilt motor mounts are almost always welded to the frame. As such,
you will need to remove the stock motor mounts from the truck frame.
This involves cutting and grinding to get a clean rail on which to weld
the new ones.

One type of custom design can be made from 2" x 3" x 3/16" steel box tubing.
Mounts such as these can mate to stock GM rubber engine mounts and are welded
to the truck frame. A single bolt in each mount secures the two mount halves
together. Another alternative is to use aftermarket mounts that bolt to the
engine block or make custom mounts, and use aftermarket urethane mating mounts.
The urethane provides a firmer engine mount and remains more stable than the
rubber during hard acceleration.

Once the larger engine is installed, you may find that the engine torque
causes the engine to twist a bit too much on the motor mounts. There are
several ways to damp or stop this unwanted action. The engine can be
chained to the frame. While this method provides very sturdy support
of the engine, the method is very unforgiving and will transmit driveline
vibration to the frame. Another method is to adapt a small hydraulic
damper between the engine and the truck frame. Such dampers can be
found in late model V6 Ford Ranger trucks. This method will provide
average damping of engine twist. Finally, an out-board stabilizer
arm can be constructed of steel and bolted to the engine block. The
other end of this arm is connected to the frame through a urethane
bushing system. This method provides both tight damping control of
the engine and vibration isolation from the frame.

SUSPENSION LIFTS & OIL PAN CLEARANCE

In general, it is much easier to perform an engine swap when a
suspension lift has been installed. In some cases it is mandatory
to install a lift to clear components in the swap. Oil pan and
starter clearances are usually tight when swapping in a V6 or
V8. Also, depending on the engine chosen, a slightly stiffer
front suspension may be needed due to the additional weight.

Most often, engine swaps done on live axle Toyotas can use the
Chevy V6 or V8 oil pan as is with a minimum 3 inch suspension
lift. However, depending on engine position and suspension lift
and travel, spring limit blocks may be required to keep the
front axle from hitting the oil pan under full suspension compression.
A lift is not mandatory when using the Buick V6 with a shallow pan,
and may or may not be required depending on the particular Ford
engine and pan used. The Ford dual sump pans seem to work well
and provide the best clearance.

Trucks equipped with IFS will have oil pan clearance problems
when converting to any of the V6 or V8 engines. To cure this
situation, either the oil pan has to be modified extensively
or a 3-4 inch suspension lift used to gain pan clearance.
Modifications can be minimized by using low profile versions
of the oil pans such as the Chevy Astro Van oil pan for the V6.
Ford pans usually provide greater clearance and require simpler
modification than the other pans. Also, it is a good idea to
install heavier torsion bars when a heavier engine is installed
in an IFS truck.

TRANSFER CASE ADAPTERS

There are two choices for transfer cases when doing an engine
conversion. One can retain the Toyota transfer case or swap
to one from another manufacturer. Possible swap choices
typically center around some version of a Dana transfer
case.

When a swap engine is pulled from the donor vehicle, the
transmission and transfer case can be used along with it.
This eliminates the need for a transmission to transfer
case adapter, but has other problems associated with it.
Custom driveshafts will be required. The shift lever may
and may not come through the floorboard in a good location,
and gaining adequate clearance between the transfer case and
floorboard may be a problem. Also, since the Toyota speedometer
cable originates at the transfer case, the cable will have to
be adapted to the new transmission or transfer case.

Adapters are available to mate non-Toyota transmissions to
the Toyota transfer case. The adapters are basically an
aluminum housing that bolts to the transmission and transfer
case and houses a large bearing and an internally splined
conversion sleeve that mates the transmission output shaft
to the transfer case input shaft. This is by far the most
common swap option. Given the fact that Toyota transfer
cases are very strong and reliable, this type of arrangement
is well suited to almost all V6 and V8 applications.
This method also allows use of the stock Toyota driveshaft
ends and retains the stock speedometer cable.

There is also an adapter available to mate the Toyota 5
speed to a Dana 300 transfer case which offers a 2.6:1
low range ratio.

Installing another engine may require that the transfer case
be relocated back a few inches. In a few cases, it may be
possible to move the entire transfer case crossmember back
and fabricate new mounts on the frame. However, it is
usually much easier to leave the crossmember in the original
position and resecure the transfer case to the crossmember
using an extension plate.

Bolt-on repositioning plates are available for this
purpose, or a plate can be fabricated and bolted or
welded into place. One means of doing this is to fabricate
a custom cross-member extension from 6" x 2" steel channel
that is notched and welded to the cross-member. The relocated
transfer case can then be bolted to this extension piece.

DRIVESHAFTS

Relocation of the transfer case rearward requires that the
front driveshaft be lengthened and the rear driveshaft be
shortened. Some conversions do not require that the transfer
case be relocated saving you from doing these modifications.
However, in all cases it is best to place engine position as
the number one priority and move the transfer case if necessary.
You will be much more pleased when you have an engine that's not
running its fan into the radiator.

Driveshafts can usually be shortened and rebalanced for about
$40 or so. Lengthening is a bit more expensive because the
entire main tube has to be replaced. This will usually run
about $70-90.

One specific driveshaft case deserves mention. Whenever the
GM 700R4 auto transmission is used, a new driveshaft made of
smaller diameter tubing is required in order to provide
clearance between the driveshaft and transmission pan. The
700R4 transmission does not have a corner notched pan like the
TH350 transmission. Be sure that there is adequate clearance
between the front driveshaft and transmission oil pan on any
conversion.

EXHAUST

When performing a V6 or V8 engine swap into a Toyota truck,
one area that requires a bit more effort is the exhaust. When
installing a Buick V6 or a Ford V6 or V8 engine there is adequate
space between the engine and frame rails, but when using a Chevy
V6 or V8 engine the space is tighter. In these cases, stock Chevy
cast iron manifolds usually will not fit because of interference
between the collector flanges and the frame rails.

There are several aftermarket conversion headers available to
solve this problem. One type, referred to as a Slick-Fit, is a
compact design that fits very close to the engine and uses rear
dump collectors on each side. The exhaust port runners dump
immediately into a collector at rear most cylinder.

Other aftermarket headers are available that are longer and
generally use a 3-into-1 or 4-into-1 design. These headers use
long primary runners that converge into a collector between the
frame rails to the sides of the transmission.

One other option is to use modified factory Chevy headers on the
swap. Over the years, several GM vehicles have used factory tubular
headers on V6 and V8 engines. These tubular manifolds can be modified
to clear the truck frame rails. This involves removing the end
flanges and lengthening the tubing sections before reattaching
the flanges further down past the frame rails.

Fuel injected engines that require use of an oxygen sensor will
need to have a threaded fitting installed in the proper place
in the exhaust tubing. These are placed in either one or both
legs of the Y-pipe, or further past the Y-pipe junction. An
original application for the engine should be studied and the
conversion installation should duplicate the sensor position
as close as possible. Note that changes in other exhaust
components in the system can affect performance of the
oxygen sensor.

COOLING

When swapping in a larger engine, it is advisable to upgrade
the cooling system to a capacity to match the new engine. It
is possible to use the stock two core radiator for Buick V6
conversions, however it will have to be modified to relocate
the hose connections for the Buick engine. It is possible to
have a radiator custom built or to try to adapt a radiator
from another vehicle for the swap. This will most likely
require cutting of the front cowl sheetmetal and fabrication
of custom mounts. For best cooling, V6 engines should use
at least a three core radiator and V8 engines almost always
a four core unit.

One alternative that is rather expensive but provides an
excellent radiator that bolts right in the truck is to buy
one of the special design radiators offered by one of the
aftermarket companies. These units bolt right up to the
stock mounting holes and are well constructed heavy-duty
copper units that provide excellent cooling. There is one
drawback to some of these though. The radiators hang low
on the truck requiring fabrication of a steel guard for
protection. A guard can be made from steel angle to protect
the lower portion of the radiator.

If necessary, there is wide variety of water necks that
can be purchased for the various engines. There are ones
available with additional threaded outlets for plumbing
heater lines if needed. Check the catalogs at your local
auto parts store for the different water neck styles.

Most V6 and V8 engines have water pumps available in both
short and long varieties. Changing from a long type to a
short one may provide the fan or radiator clearance you
need. A short pump is always required on V8 conversions.

ENGINE FANS

There are three types of fans that can be used in an engine
swap: a stock-type clutch fan, a flex fan, and an electric
fan. Each of these has its advantages and disadvantages.

A stock-type clutch fan provides the best cooling, good
efficiency, and excellent reliability. Its blades are fixed
pitch and provide considerable airflow when turning. The thermo
clutch unit turns the fan on or off depending on engine
temperature. This helps maintain the engine at a constant
temperature and helps relieve extra load from the engine.
Unfortunately, clutch fans almost always require alot of
depth due to their fan pitch and shaft design.

Flex fans maintain a sharp pitch at low rpm to provide
lots of airflow, but flatten out as rpm rises to help keep
an even airflow going and relieve some load from the engine.
They are always turning and constantly place some load on
the engine. Flex fans usually provide less cooling ability
than the other types, but have the important advantage of
being fairly thin and not requiring much mounting depth.

Electric fans come in a variety of sizes and styles, and
can be thermostatically controlled to turn on and off with
changes of engine temperature. They have the advantage of
being mounted either in front of or behind the radiator,
and as such, are the most versatile of the fan types.
Electric fans are a popular choice for V8 conversions.
Where space is tight, two small fans can be used in place
of one larger one. The one downside is that electric fans
may be the least reliable. Also, don't assume since they
are electric, you get something for free. The fan pulls
power from the electrical system and the engine must still
turn the alternator to provide power to the battery.

If using a mechanical fan, fan spacers may be required
to locate the fan out to clear the front of the engine
and belts. These are available in all sizes, typically
in 1/2 inch increments.

FUEL SYSTEM

There are a number of different fuel delivery systems
in use and the fuel pressures differ in each system.
Below is a listing of various systems and their associated
fuel pressures.
Carbureted 5-7 psi
Holley Pro-Jection 7-12 psi
GM Throttle-body Injected 12-15 psi
Toyota Multi-port Injected 30-40 psi
GM Tuned Port Injected 35-50 psi
Ford Multi-port Injected 35-50 psi

When swapping engines it is often necessary to swap fuel
pumps as well. Depending on engine configuration it may
not be possible to use a mechanical fuel pump and an
electric one may have to be substituted. Carbureted Toyota
trucks use a mechanical engine-mounted fuel pump, while
fuel injected versions use a high pressure electrical
tank-mounted unit. If a new electric pump is used, the
original Toyota pump can be left in the gas tank and the
new pump added slightly ahead of the gas tank. The old
Toyota fuel pump is not energized but can be used as a
backup pump if necessary.

Electric power for the fuel pump in most EFI systems is
supplied via the engine harness. It is also a good idea
to add a large canister type fuel filter spliced in-line.

A word of caution when using electric fuel pumps is in
order. Factory equipped fuel injected vehicles always
incorporate a safety circuit to turn off the electric
fuel pump any time the engine stalls. This is to prevent
fire in case a fuel line were to burst. The engine will
stall, but without such a circuit, the pump would continue
to spray gas into the engine compartment.

The fuel pump circuit generally works as follows. When the
ignition switch is turned to the start position, the fuel
pump is energized directly (possibly through a relay) by
this switch. Once the ignition switch is released to the
run position, the fuel pump is energized only if has an
indication that the engine is actually running. This signal
is provided by the airflow meter on a Toyota engine or
sometimes by an ignition signal on other engines. If this
signal is not present, the circuit assumes the engine is
not running and turns the fuel pump off. When adding an
electric fuel pump in an engine swap, it is a good idea
to provide such a safety circuit for the fuel system.

CHARGING SYSTEM

Whenever a larger engine is installed, it is a good idea
to upgrade the alternator the match the new engine. Brackets
are available to allow mounting of the stock Toyota alternator
to a Chevy V6 or V8 engine. However, it is often desirable
to swap to a higher rated alternator and usually one with
a built-in regulator will work best. You can also use the
increased capacity to help run any extra lights or accessories
you may have. Using the alternator that came with the new
engine is easy because it already has the proper mounting
brackets, and wiring it is quite simple assuming it is an
internally regulated type.

The new alternator can be spliced into part of the original
Toyota wiring. The following description gives a general
procedure for wiring up the new alternator. Specific wiring
details will vary with the alternator being used and the
particular year model of the truck.

The B+ terminal of the alternator is connected to the large
wire in the Toyota harness or connected directly to the
positive battery post using a 6 or 8 gauge wire. The case
of the alternator is grounded using the original black
Toyota wire. The terminals on the alternator are connected
to the white (+) and yellow (charge) wires in the Toyota
harness. Again these may vary with the specific swap parts.

Once the swap is complete, ensure that the battery used in
the truck has sufficient capacity to easily crank over the
bigger engine you've installed.

POWER STEERING

When performing an engine swap it is possible to either use
the original Toyota power steering pump or use the one that
came on the new engine. The Toyota pumps use an external
fluid reservoir mounted either directly over the pump or
on the inside of the fenderwell. Brackets are available to
allow mounting of the stock Toyota power steering pump from
a 4 cylinder engine to a Chevy V6 or V8 engine, or you can
fabricate your own mounts for your particular needs.

The GM and Ford power steering pumps use an integral reservoir
mounted to the back of the pump. Since one of these is already
mounted to your new engine and the belt system has been done
for you, it is usually easier to use this instead of the
original pump.

To adapt the pump to the Toyota steering box, simply run new
power steering hose to plumb the low pressure side of the pump.
For the high pressure side it is usually best to use the stock
hose that came on the engine. This will route correctly between
the pump and the engine. Shorten it as needed by cutting a
portion of the steel tube end off. Replacing the tubing flare
nut on the pump end with the one from the original Toyota hose,
and reflare the tube end. If you cannot flare the tube end to
fit the pump, hose adapters are also available to make the
connector conversion. The original power steering cooler can
be retained behind the grille and standard power steering
fluid can be used in the system.

ENGINE SENSOR WIRING

When performing a swap that uses a computer controlled fuel
injected engine, it will be necessary to install a wiring
harness to accommodate the computer and sensors for the new
engine. You can either pull the harness from the engine donor
vehicle or purchase one of the aftermarket harnesses on the
market.

When using a harness from the donor vehicle, it will be
necessary to carefully separate the portions of the harness
that are engine related form those that are not. This can be
a long and tedious process, but it can be done. A simpler,
yet more expensive solution, is to purchase a harness made
specifically for the engine swap you are doing. These
harnesses are well made, many times using the same components
as GM and Ford. The advantage is that they are made fresh
without all the non-engine wiring. They are easy to use and
provide a clean, professional appearance. Also, you do not
have to worry with wiring gremlins when you have so much
else to do during the conversion.

STARTER/IGNITION WIRING

The original Toyota V+ battery cable can be connected to the
starter on the new engine, or it can be replaced with a longer
one if necessary. Depending on the type of engine you use it
may have a starter mounted solenoid or an external unit such
as some Ford engines use. Wiring of the starter is
straightforward and can easily be integrated into the stock
Toyota wiring harness.

One item that is never mentioned in most Toyota swap info is
that the ignition switched solenoid line on Toyota trucks
cannot source sufficient current to reliably engage some
domestic starter solenoids. Therefore, it is necessary to
wire the solenoid line to a relay and provide a switched V+
line from the battery through the relay. Use the original
Toyota ignition signal to energize the relay. Voltage can
be supplied to the new ignition coil via the original Toyota
harness wire.

TACHOMETER

The new coil can also be spliced into the original tachometer
wire to display engine speed on the factory tachometer. If
the original engine was a V6 and the swapped in engine is a
V6, the stock tachometer will display the correct engine
speed. However, if the stock engine was a 4 cylinder, the
tachometer will display 50% greater rpm than actual for a
V6 engine, or 100% greater rpm than actual for a V8 engine.

There are two ways to cure the problem and have a tachometer
display actual rpm. One is to buy an aftermarket tachometer,
and two is to
recalibrate the stock one.

The Toyota tachometer accepts the pulsed ignition signal
from the coil and converts it into a proportional DC signal
that drives an analog current meter in the dash to display
engine RPM. Its reading can be scaled to correctly display
the correct engine RPM by adding a calibrated resistive
shunt to the meter input.

A 5k ohm trim potentiometer is placed across the input
contacts to the tachometer meter. This is done directly
at the meter posts inside the instrument cluster. For
this purpose, it is best to use a small 10 turn potentiometer
to provide easier calibration of the tachometer. This
potentiometer can be purchased at almost any electronics
store. Solder wires to potentiometer and find a way to
add it to the wiring at the back of the meter. The figure
below shows schematically how this is done.

Once installed you will be able to recalibrate, or scale,
the tachometer reading by adjusting the potentiometer.
By running the engine and using another accurate tachometer
as a reference, adjust the potentiometer until the engine
RPM readings are both the same. You now have a factory
tachometer that reads accurately for your V6 or V8 engine.

CHECK ENGINE LIGHT

Late model computer controlled engines have a Check Engine
light in the dash to indicate when the computer has detected
a fault signal from some engine sensor. When swapping in a
late model engine, it is helpful to retain this feature.

For Toyota trucks that were not originally equipped with
such a dash light, a simple 12V light installed in the dash
will work. Trucks that were originally equipped with the
light can use the signal from the new engine by splicing
into the wire in the Toyota harness.

THROTTLE LINKAGE

The original Toyota throttle cable can be used in most cases.
Fortunately, it is long enough to reach most all carburetors
and injector throttle body units. It will be necessary to
fabricate a new end piece to mate the cable to the new
engine and a custom cable bracket may be necessary. Universal
aftermarket throttle cables are also available that can be
adapted to work on a conversion.

Once complete, it is a good idea to ensure the cable operates
smoothly through its entire range, and that you truly get
full throttle opening when the pedal is pushed to the floor.
Depending on the carburetor or injector unit used, you may
have to shorten or lengthen the throttle lever to dial in
just the right ratio to match the movement of the Toyota
pedal assembly.

CRUISE CONTROL

It is possible to retain the function of the original cruise
control because the controller receives its speed signal
from the speedometer input. You can check for this feature
on an aftermarket unit as well. Enable the cruise control
while driving in fourth or fifth gear. Note the speed.
Disengage the cruise control by tapping on the clutch or
brake pedal. Now shift down one gear and push Resume on
the cruise control. If the truck cruises at the same speed,
your system works from the speedometer input and the cruise
control can be retained with the new engine.

When switching to an automatic transmission, the clutch pedal
is often removed. This may trip the clutch switch that
disables the cruise control. To restore its function, it
will be necessary to either electrically override the function
or mechanically disable the switch.

AIR CONDITIONING

When swapping in another engine, you can either use the
original Toyota air conditioning compressor or the compressor
that came with the new engine.

Brackets are available to allow mounting of the stock Toyota
air conditioning compressor to GM engines and brackets should
soon be available for the Ford engines as well. Some engines
may require that you fabricate your own custom bracketry. By
reusing the stock Toyota compressor, all cooling lines and
electrical wiring can remain unmodified. With care, you can
even install the new engine without ever leaking the a/c system.

Many times it is easier to use the air conditioning compressor
that came with the new engine. This is especially true when
using an engine with a serpentine belt. While the compressors
on such an engine usually rotate in the same direction as one
on a non-serpentine belt engine, retrofitting a stock Toyota
compressor will require somehow changing the pulley to one
that can accept the serpentine belt.

If a different compressor is used, it will be necessary to
modify the hoses to mate the compressor to the rest of the
system. This will require making custom a/c hoses. One way
to do this is to use compressor fittings, and possibly some
of the hose, that comes with the new compressor and mate these
to some of the original Toyota lines. The metal end of the hose
that attaches to the condenser at the front grill can be cut and
mated to the high pressure compressor line. The low pressure hose
can be adapted as well by using the metal end of the original hose
that meets at the firewall.

A competent repair shop can mate the hose pieces for you
using high pressure crimp connectors. Depending on the
compressor used, you may also need to install inline charging
and suction valves as the originals were mounted to the
Toyota compressor. In some cases using GM compressors,
where a metal tubing header is used on the compressor, the
header may not route the hoses well in the Toyota engine
compartment. There is a variety of these headers available
in all shapes and sizes. Also, it is possible to have a shop
cut and rotate the tube outlets to face in the proper direction.

The original Toyota electrical connector that hooks to the
compressor is a single conductor and provides a 12V signal
to actuate the magnetic clutch and turn on the compressor.
The appropriate GM or Ford connector can be spliced into
this wiring to hookup the new compressor. Most of these
connectors are two conductor, one the 12V signal and the
other ground. The ground wire from the connector can be
attached to a bolt on the new compressor.

The new compressor should work fine on the Toyota system.
An a/c compressor is essentially a dumb device. It pumps
when it is told to and is either on or off. The a/c control
circuit is responsible for telling the compressor when to
turn on and off. In the Toyota, this is done by the a/c
amplifier, a circuit that monitors certain sensors in the
system and decides how to control the compressor.

One function of the a/c amplifier is to monitor engine
rpm and turn off the compressor as engine idle drops
below about 600-700 rpm to prevent the engine from stalling.
The speed at which this unit cuts out is often adjustable
at the a/c amplifier under the dash. When a new engine is
installed, it is necessary to retain the tach input to the
a/c amplifier to allow it to turn on the compressor.
However, with a V6 or V8 the engine rpm will be 1.5 to 2
times higher for a given rpm and the compressor will probably
never turn off due to low idle speed.

GAUGES

Aftermarket gauges can be added to monitor oil pressure and
water temperature, but many times you can reuse the stock
gauges and sending units if you choose. This keeps the dash
stock and retains the functionality of the original gauges.
The original Toyota oil pressure sender can be added to the
swap engine using a metric to American thread adapter. In some
cases, the original Toyota temperature sender can be threaded
directly into the swap engine, or an adapter may be required.
The stock voltage gauge can be retained unchanged.